Spark plug



A 1953 H. P. PHILLIPS ET AL 4 ,54

SPARK PLUG Filed Oct. 8, 1951 A? M 32 77. 5- INVENTORS,

Patented Aug. 11, 1953 SPARK PLUG Harold P. Phillips and Rex J/L.Dutterer, Hastings, Mich., assignors to Hastings Manufacturing Company,Hastings, Mich., a corporation of Michigan Application October 8, 1951,Serial No. 250,266

2 Claims.

This invention relates to improvements in a spark plug.

The main objects of this invention are:

First, to provide a spark plug in which the electrodes are effectivelyprotected against erosion and against accidental injury in handling butat the same time one in which the ground electrodes may be easily andeffectively gapped or adjusted.

Second, to provide a spark plug having these advantages in which theground electrodes may be easily adjusted through a considerable range toadapt the same for the requirements of particular engines.

Third, to provide a spark plug structure having these advantages whichmay be very economically produced.

Objects relating to details and economies of the invention will appearfrom the description to follow. The invention is pointed out in theclaims.

A preferred embodiment of the invention is illustrated in theaccompanying drawings, in which:

Fig. 1 is a side elevational View of a spark plug embodying ourinvention.

Fig. 2 is an enlarged inner end view, a tool being shown in section andpositioned to adjust one of the ground electrodes.

Fig. 3 is a fragmentary view partially in longitudinal section on a linecorresponding to line 3-3 of Fig. 2.

Fig. 4 is an enlarged fragmentary View in section on a linecorresponding to line 4-4 of Fig. 2.

It should be understood that all of these views are considerablyenlarged and that no effort has been made to show parts in their exactproportions. This is done for clearness and convenience in illustration.

In the accompanying drawing I represents the insulator portion of aspark plug and 2 the insulator shell. The mounting of the insulatorwithin the shell is not illustrated as that forms no part of our presentinvention. The insulated electrode 3 is suitably mounted and sealedwithin the insulator and is supported with its inner end projectingcentrally of the shell. The shell is externally threaded at 4 to bescrewed into a suitable bore provided therefor in the cylinder block orhead. It will be noted that the insulated electrode 3 terminates withinthe shell, its inner end being preferably flush with the inner end ofthe shell.

The ground electrodes 5 are fixedly secured to the shell in current andheat transfer relation thereto. This connection is formed by formingangularly spaced slots 6 in the end of the shell and opening to theinner end edge thereof. The electrodes 5, which are desirably of fiatsection, are disposed in these slots and welded thereto as indicated atl in Fig. 4. The electrodes are disposed within the shell and guardedthereby with their inner ends free.

The electrodes are desirably formed of fiat bendable stock. They arepositioned in angular relation to each other. In Fig. 2 there are twoelectrodes 5 and they are positioned at right angles relative to eachother with their inner ends adjacent but spaced sothat a tool such as ascrewdriver blade 8 may be fulcrumly supported on the end of oneelectrode and engaged with the adjacent electrode for adjusting itrelative to the insulated electrode 3.

For the most satisfactory performance the spark plug gaps'should be suchas to meet the requirements of the particular engine, either as originalinstallation or replacement spark plugs, or cleaned spark plugs. Theground electrodes of applicants spark plugs are readily adjusted at thefactory to meet the requirements of a particular engine, or are adjustedby the installer.

Spark plugs having multiple ground electrodes are generally recognizedas being longer lasting than single electrode plugs, inasmuch as theground electrodes are not eroded or disintegrated as rapidly. In theapplicants structure the multiple ground electrodes are so arranged thatthey are well protected within the shell and at the same time may bevery conveniently and accurately spaced or gapped. The applicants do notwish to be understood as urging that sparks pass between the insulatedelectrode and all of the multiple ground electrodes at the same time,although this might occur; applicants observa tion is that the sparkpasses between the insulated electrode and the ground electrode which isclosest thereto until that electrode is eroded to such an extent thatthe spark passes between another ground electrode and the insulatedelectrode, and this continues more or less in rotation; that is, whenone ground electrode is worn or eroded so that its gap exceeds that ofanother, the sparking shifts. However, it is important, as stated, toprovide for accurate and easy adjustment when the plugs are manufacturedand also when they are installed as replacements or renewals.

We have illustrated and described our invention in three very practicalembodiments thereof. We have not attempted to illustrate or describe theinvention in the various adaptations of which it is capable as webelieve the disclosure made will enable those skilled in the art toembody or adapt the invention as may be desired.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. A spark plug including an insulator and an insulated electrodecarried thereby and projecting from its inner end, a tubular metallicshell for said insulator, the insulated electrode being supportedcentrally of and terminating within the shell, the shell havingangularly spaced slots in the wall thereof extending axially from itsinner end edge, and bendable ground electrodes of flat section disposedvertically edgewise with their outer ends in the slots and weldinglybonded to the walls thereof and with their inner ends free andpositioned within the shell and guarded thereby and in side overlappingrelation to the insulated electrode and laterally bendably adjustablerelative thereto, said ground electrodes being angularly disposedrelative to each other with their free ends in spaced, nonoverlappingofiset relation to enable a tool being introduced between their ends andfulcrumly positioned on the free end of a selected electrode and inengagement with the inner side of the free end of the adjacent electrodeto facilitate the outward adjustment of the ground electrodes relativeto the insulated electrode, the free ends of the ground electrodes beingspaced inwardly from the shell to facilitate the inward adjustmentthereof with a tool in fulcruming engagement with the interior of theshell.

2. A spark plug including an insulator and an insulated electrodecarried thereby and projecting from its inner end, a tubular metallicshell for said insulator, the insulated electrode being supportedcentrally of and terminating within the shell, and bendable groundelectrodes having their outer ends fixedly secured to the wall of theshell in angularly spaced relation with their inner ends free andpositioned within the shell and guarded thereby and in side overlappingrelation to the insulated electrode and laterally bendably adjustablerelative thereto, said ground electrodes being angularly disposedrelative to each other with their free ends in spaced, non-overlappingofifset relation to each other to enable a tool being introduced betweentheir ends and fulcrumly positioned on the free end of a selectedelectrode and in engagement with the inner side of the free end of theadjacent electrode to facilitate the outward adjustment of the groundelectrodes relative to the insulated electrode.

HAROLD P. PHILLIPS. REX J. L. D-UTTERER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,623,468 Ellett Apr. 5, 1927 2,270,765 Nowosielski Jan. 20,1942 2,294,248 Smulski Aug. 25, 1942 2,368,889 Setterblade Feb. 6, 1945

